The EI tach is a good one with just a couple of caveats. It's smaller than the original, which is sort of a good thing, except that it can give your panel a sort of hodge/podge look. Also with regard to cosmetics, to my eye the EI tach has a distinctly 1980's Radio Shack aesthetic. One way to deal with this is get several other EI instruments then it all looks intentional. Problem there is the amount of money you might end up spending, after a while it might make sense to get an all in one EI like the MVP-50, which of course has a digital tach, and everything else too.
On the plus side, the stand alone EI tach rounds RPMs to the nearest 10, so it doesn't constantly jump around like some other digital tachs.
